1. Field Of The Invention
The present invention relates generally to gas flaring methods and apparatus, and more particularly, but not by way of limitation, to a method and apparatus for flaring gas mixtures such as the gas mixtures emitted from landfills while retarding the backward propagation of flame in the gas mixtures.
2. Description Of The Prior Art
A great variety of waste and vent gas flaring methods and apparatus have been developed and used heretofore. Such methods and apparatus generally involve conducting the waste or vent gases to one or more burners which are elevated or which are positioned within the lower portion of a vertical stack. Air is mixed with the gases either just before the gases enter the burner or after the gases are emitted from the burner and the gases are combusted. The products of combustion are discharged into the atmosphere.
In systems where air is mixed with the gases just prior to entering the burners whereby an air-gas mixture flows through the burners, the burners have been equipped with means for retarding flashbacks, e.g., structure through which the air-gas mixture flows which prevents or retards backward flame propagation. Examples of such burners are described in U.S. Pat. Nos. 1,420,405 dated June 20, 1922; 2,627,910 issued Feb. 10, 1953; and 3,807,940 issued Apr. 30, 1974.
In flaring combustible gas mixtures which at their source contain flammable gases and combustion supporting gases such as oxygen or air, it is mandatory that the backward propagation of flame through the advancing mixture toward the source of the mixture be retarded since if such propagation takes place, fire and/or explosion can result. This problem is particularly severe in the flaring of gas mixtures formed in landfills since the flaring must take place at varying flow rates and flowing pressures.
The degradation of buried refuse and wastes in landfill areas often produces gas mixtures which collect within the landfill. The presence of such gas mixtures in the landfill presents a hazardous condition in that the gas mixtures can leak to the surface whereby they produce a nuisance such as by causing an odor problem, and they may be ignited. In order to eliminate the hazards presented by the formation of gas mixtures in landfills, such mixtures have been withdrawn therefrom and flared. However, because in the act of removing gas mixtures from landfills air is often introduced and combustible mixtures formed, problems have been encountered as a result of reverse flame propagation.
By the present invention, a method and apparatus for efficiently flaring gas streams including combustible gas mixtures which retard reverse propagation of flame are provided.